Tamper-proof closures of the type under consideration are usually applied to glass bottle finishes which are relatively rigid structures as exemplified in U.S. Pat. No. 3,329,295. In such structure the inherent nature of the glass is inflexible and the locking shoulder thereon will not deflect and thus will not permit the tamper-indicating band on the cap to slip off.
Furthermore conventional arrangements of severable tamper-proof band applications include a plurality of weak bridges which connect the band to the cap which must be simultaneously broken to release the band from the cap. Excessive resistance to unthreading of the cap develops and, frequently after great effort, the band slips over the locking shoulder thus frustrating the tamper indicating feature.